drop if (exporter=="BEL" | importer=="BEL")
drop if (exporter=="HAI" | importer=="HAI")
drop if (exporter=="ISL" | importer=="ISL")
drop if (exporter=="SAR" | importer=="SAR")
drop if (exporter=="DRP" | importer=="DRP")
drop if (exporter=="TNT" | importer=="TNT")
drop if (exporter=="AUS" | importer=="AUS")
drop if (exporter=="IRN" | importer=="IRN")
drop if (exporter=="ARG" | importer=="ARG")
drop if (exporter=="MAL" | importer=="MAL")
drop if (exporter=="FIJ" | importer=="FIJ")
drop if (exporter=="NEP" | importer=="NEP")
drop if (exporter=="NIR" | importer=="NIR")
drop if (exporter=="ELS" | importer=="ELS")
drop if (exporter=="NOR" | importer=="NOR")
drop if (exporter=="JPN" | importer=="JPN")
drop if (exporter=="SWE" | importer=="SWE")
drop if (exporter=="PHI" | importer=="PHI")
drop if (exporter=="POR" | importer=="POR")
drop if (exporter=="THA" | importer=="THA")
drop if (exporter=="MEX" | importer=="MEX")
drop if (exporter=="CAN" | importer=="CAN")
